Fujitsu Conducts Field Trial of Anomaly Detection System Using Optical Fiber Technology for Thermal Power Stations

Fujitsu plans to commercialize this system in the future and develop business not only with power stations but also other facilities, such as chemical plants.

Background

In maintaining stable operations at thermal power station facilities, the key to early detection of anomalies is monitoring the temperature changes of a variety of places, including fuel pipes(3) and boiler flues(4), and having a constant grasp on the status of such facilities. With previous discrete temperature sensor anomaly detection, however, as each sensor required a communication cable, and because of the difficult constraints unique to thermal power stations, there were limits to the possible number and placement of sensors.

Temperature measurement through an optical fiber features the ability to measure temperature along a several-kilometer long optic fiber at successive 10 centimeter intervals. Furthermore, because it uses light, instead of electricity, to measure temperature, it is not restricted by explosion prevention measures, providing the added benefit that it can be installed in a wide variety of facilities related to a power station. It is also possible to lower deployment costs compared with using discrete temperature sensors. In order to develop an anomaly detection system that takes advantage of the features of this sort of optical fiber, Fujitsu has conducted joint research with Tohoku Electric Power.

Details of the Field Trial

Fujitsu and Tohoku Electric Power used this optical fiber multipoint temperature sensing technology to continuously monitor temperature changes in the fuel pipes, steam pipes(5), and boiler flues at Tohoku Electric Power's Akita power station from June 2014 to March 2015. Based on Tohoku Electric Power's expertise in using temperature changes in power station-related facilities to detect facility anomalies, the two companies conducted a field trial involving an analysis of the measurement results and more refined real-time detection of facility anomalies.

Results of the Field Trial

By analyzing the temperature measurement data for the steam pipes, the two companies were able to detect irregular condensation of steam and the occurrence of blockages. Furthermore, by comparing the timing of rises and falls in steam pipe and fuel pipe temperatures, they were successfully able to grasp whether the status of the various pipes was normal or not.

In addition, even in boiler flues, which expel high temperature exhaust gasses reaching 120degC, and which are subject to continuous vibrations, the companies were able to monitor temperatures for 60 consecutive days and carry out real-time temperature monitoring using this technology, even in such a high-temperature, high-vibration environment, showing it was also possible to detect anomalies in this type of facility.

Future Development and Targets

As it succeeded in confirming the effectiveness in this field trial, Fujitsu aims to commercialize a facilities management solution based on this system, not only for power stations but for a variety of plants.

(1) Optical fiber multipoint temperature sensing technology

(2) Discrete temperature sensors

Semiconductor-based temperature sensors, thermocouple-based sensors, and so forth. Normally used with power and communications cables installed at each temperature measurement point.

(3) Fuel pipes

Pipes to transport heavy oil in thermal power stations.

(4) Boiler flues

Ducts that expel exhaust gasses from combustion in the boiler.

(5) Steam pipes

Pipes wrapped around the fuel pipes for transporting high-temperature steam. They play the role of a heater in keeping the heavy oil in the fuel pipes at the proper viscosity for transport.